FIG. 1 illustrates the basic architecture of a cellular radio network in form of a UTRAN (Universal Terrestrial Radio Access Network) network, connected to the Internet 170 and a WLAN. The WLAN normally comprises at least one radio Access Point, AP, 165 normally connected to an Access Point Controller, APC, 162. The cellular radio network comprises a GGSN 110 connected to a SGSN 120 which in turn is connected to a RNC 130. A dual mode UT (User Terminal) 140, having both UTRAN and WLAN capability, can establish a UTRAN radio connection through its first data port 141 with Base station Node B 150 and a WLAN radio connection through its second data port 142 with the AP 165 of the WLAN. Node B 150 is connected to RNC 130. The WLAN may in a conventional manner be connected to the SGSN 120 or to the GGSN 110 or to the Internet 170, FIG. 1 illustrates the case wherein it is connected to the GGSN 110, possibly via an AR (Access Router) and/or an IP-network, not illustrated in FIG. 1. A data communication session can be established between the UT 140 and a communicating party connected to the Internet 170. The data communication session may in a conventional manner be realised by a PDP (Packet Data Protocol) context session between the UT 140 and the GGSN 110, in accordance with the 3GPP standard for packet radio data services.
In case of a handover of a PDP context session from the UTRAN routing path to the WLAN routing path, a lot of signalling is needed and high delays are expected if a lossless handover should be performed since the user data, i.e. downlink PDP-IP-packets, that have been sent to and cached in the corresponding UTRAN node, i.e. the RNC 130, but not yet transmitted to the user terminal UT must be forwarded back across the UMTS (Universal Mobile Terrestrial System) core network, i.e back to the GGSN 110, to be routed further to the UT 140 via the APC 162 and AP 165.
Another problem is that the cellular radio access network, i.e the RNC 130, in the network architecture illustrated in FIG. 1 has no access to the wireless data network's, i.e. the WLAN's, radio resource management information, and the WLAN has no access to the cellular radio network's radio resource management information, hindering an efficient multi radio resource management of the entire integrated UTRAN-WLAN network.
None of the above identified problems are admitted by the applicant to constitute prior art.